Anyone who
has ever driven a car has heard that talking on a cell phone increases reaction
time and might lead to more accidents. Common sense tells us that cell phones
and cars simply don’t mix, but it’s next to impossible to keep the two
separate. So we found ourselves asking the question, is there any truth to
cell phones increasing reaction time? We hypothesized that distractions
requiring greater concentration hinder the ability to react. We predict that
talking on a cell phone will increase reaction time, and that text messaging
will increase it even more.

To test
this hypothesis, we designed an experiment that would simulate slamming on the
brakes in a car. We had two subjects take turns running four variations of the
same test, alternating back and forth between people to nullify muscle memory.
During the test, each subject sat in a chair that was two feet away from a
wall. The subject would place their right foot at a mark 25 centimeters above
the ground on the wall. We would then randomly drop a yardstick from 90
centimeters above the ground, three inches to the left of the mark, and the
subject would have to slam his/her foot against the wall to stop the before it
hit the ground. We then recorded the distance in centimeters that the
yardstick had fallen, and used the equation t = √(distance/490 cm/sec2)
to convert distance to time. The first test we ran was our experimental
control, in which there were no distractions in the room. This gave us the
base reaction times. We used this to determine how much the subject’s reaction
time increased when using a cell phone. The second test we ran was to have the
subject engaged on the phone in an “easy conversation” (questions like “hi,
how’s it going”) while stopping the yardstick. The next test we ran involved
having the subject engaged in a “hard conversation” (questions like “explain
mitosis”) while trying to stop the yardstick. The last test we ran involved
the subject text messaging while trying to stop the yardstick.

Our mean
experimental control reaction time was .19 seconds. Our results indicated that
reaction time is significantly worse when a person is engaged in an easy
conversation (mean = .20 seconds, P-value = .0456), worse yet when engaged in a
hard conversation (mean = .22 sec., P=value = .01059), and increases by an entire
tenth of a second when text messaging (mean = .29 sec., P-value = .000592).

Our results were consistent with
our hypothesis, and unfortunately do not bode well for the avid text
messager/driver. As we predicted, the reaction times got progressively worse,
increasing slightly with an easy conversation and substantially with text
messaging. We adequately tested our hypothesis, but also had a few experimental
errors. First, we used only two test subjects, one boy and one girl, yielding
only two sets of experimental data. This is not an extensive enough sample
size. If performed again, the experiment should be done with a much larger
number of test subjects. Second, to nullify muscle memory we had subjects
alternate between tests, but if performed again there should be a five-minute
break between scenarios to further prevent muscle memory. Third, we could not
find a suitable environment that would allow the yardstick to fall
indefinitely, without hitting the ground. Thus it is possible the test subject
would have stopped the yardstick if they had had more time to do so. The
experiment will do better if conducted in a way that allows the stick to keep
falling until the subject stops it.

There was only one study on the
class webpage that resembled ours, and it tested music’s affect on reaction
time. Blansit et al 2005 found that music did not significantly alter reaction
time. Our results are not consistent with theirs, however, as we ran tests
that involved more concentration on the subject’s part than listening to music
alone. Our subjects’ reaction times were thus more hindered.

We did not modify our hypothesis.
Perhaps if the data were collected from a larger number of test subjects we
would see a more accurate trend in increased reaction time, which would still
be consistent with our predictions. As of now, we would encourage everyone to
go ahead and hang up their phones before getting behind the wheel. It’s ok.
You can always call them back.